where to go ? any ideas ?

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Re: where to go ? any ideas ?

earthworm
these rather cheap fiber media converters, with or without usb on one side, are nevertheless a great idea, this is an interesting thread, thanks a lot for all the related info.
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Re: where to go ? any ideas ?

sailplane
In reply to this post by Marc Martin
Marc Martin wrote
>  Sailplane, that's true, but a short ethernet cable isn't an efficient
> antenna at those frequencies. (For 100 MHz, the most efficient antenna
> would be 1.5M or 69".) They also use two oppositely-charged wired for
> each bit. And both the voltage and current are very low.

Yes, I was going to say, I react to a lot of stuff, but Ethernet wiring is pretty low on that list, and something I consider to be better than any alternatives.

Marc
That's interesting. I always find it worse when ethernet cable is connected to my laptop. Maybe my laptop's ethernet adapter is the problem. I haven't measured it with a shorter cable, usually the cable I connected was at least 6 feet.  I had an ethernet cable running along the head side of my bed for years, perhaps that made me more sensitive.

When I was doing a lot of measurements I was surprised to find the ethernet could be picked up by my radio for at least 6 feet.. I know the radio is quite good at amplifying signals though, but it was quite a bit stronger than what the laptop itself was emitting. That's when I started looking for alternatives and I've been very happy with the USB fiber. Sometimes I have to share my fiber connection to another laptop by Ethernet and I always notice it feels worse.. but the other laptop is plugged into the AC, and ethernet cable will carry any electric currents to my laptop.

Even if there were no RF emission from ethernet, all routers are two prong, and their AC adapter usually causes some E fields, which then ended up in my laptop. Those fiber adapters have a metal body and they can be grounded, that way any ethernet plugged into it grounds it's E field, and it can even ground a router that is plugged into it. If the router is grounded then anything plugged into it will discharge through the router. I did that for my VOIP box, otherwise I would get high E fields on my cord phone, because the router's E fields went to the Voip through ethernet.
Basically, I find routers and ethernet problematic... I'm not sure how you can know it doesn't do anything to you/compare unless you have ever used fiber. I just had a hunch, because for a long time I had been trying to get rid of E fields running on ethernet.

I use a computer every day.. if you don't use it for a while and then use it and it's all okay, that would be one way.. but I need it for my work.
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Re: where to go ? any ideas ?

casper
Sailplane, you bring up a lot of good points. I have also been thinking about the electric fields. They are for sure a problem, but what is interesting in my personal case, is that my laptop is always grounded. I noticed a long time ago that an ungrounded laptop is no good. And that means a laptop running with 2 prong adapter, or even 3 prong without DC ground. This may also have been pulling some of the ethernet fields into the ground, making ethernet less of a problem.

Also, previous long-term exposure I think can be sensitizing. So you might have a point there with your bed.

Finally I wonder, did you consider EMI coming into your house through your ISP, and then feeding into your whole home ethernet network? Maybe the problem is not the ethernet per se, but the EMI coming from the ISP?

I ask because Jeromy @ EMFAnalyis just recently published this article, about people becoming sick from upgraded noisy ISP infrastructure:

https://www.emfanalysis.com/fiber-optics-increasing-electrical-sensitivity/

The solution here is again to optically isolate. In this case you want a media converter placed on the ISP input to the house, so that the noise from their cable never enters the home.

I know the ethernet cable coming into my home from the ISP has a distinct pulsing noise on it. I don't know if that is contributing to my problems, but for now it is also isolated away by the media converter.


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Re: where to go ? any ideas ?

Karl
In reply to this post by sailplane
Here there were three 30-50 foot cables (unshielded) and one 60+ foot cable, and I didn't feel good when the network was powered up.  But for now I'm crossing my fingers and hoping that the short cable to the media converter won't be too much of a problem.

I looked for USB fiber adapters, but ended up going with this because I don't know yet if it will help and it's cheaper.  The secondary reason is that USB has a higher voltage (on the power side, at least), and it's shared with any external keyboards or mice I plug in.  (Integral keyboards and trackpads in laptops might still use PS/2, but I'm not sure.  They did for a long time because there was no advantage to USB for something that's hard-wired to a chip on the board.)
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Re: where to go ? any ideas ?

Karl
In reply to this post by casper
Casper, I thought of another way to figure out which type of fiber the media converters need, but it requires some careful measurement.

If you shine a low-power laser pointer directly at the fiber in the receptacle (which you can see pretty easily), then whether the reflected light shines directly back into the pointer or off to one side will tell you whether it's PC/UPC or APC.  The tricky part is that the laser needs to be aligned with the PLUG, which is not necessarily square with the metal box.

The angle of an APC plug is 8 degrees (0.14 radians), and the skew is in the same direction in all plugs (or they wouldn't fit).  That should make it a bit easier to distinguish between an APC plug and a misaligned test.
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Re: where to go ? any ideas ?

sailplane
Karl wrote
Casper, I thought of another way to figure out which type of fiber the media converters need, but it requires some careful measurement.

If you shine a low-power laser pointer directly at the fiber in the receptacle (which you can see pretty easily), then whether the reflected light shines directly back into the pointer or off to one side will tell you whether it's PC/UPC or APC.  The tricky part is that the laser needs to be aligned with the PLUG, which is not necessarily square with the metal box.

The angle of an APC plug is 8 degrees (0.14 radians), and the skew is in the same direction in all plugs (or they wouldn't fit).  That should make it a bit easier to distinguish between an APC plug and a misaligned test.
"single mode cable is coated with yellow outer sheath, and multimode fiber is coated with orange or aqua jacket."
https://community.fs.com/blog/single-mode-fiber-how-much-do-you-know.html

The fiber adapter will state in instructions if it's single mode or multimode. If you want to combine different brands you have to make sure they use the same light frequency and IEEE protocol.
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Re: where to go ? any ideas ?

sailplane
This post was updated on .
In reply to this post by casper
casper wrote
Karl yes, good point. Sorry I completely forgot to talk about it. I also figured it out only after I placed my order. I'm still not sure what type I really should be using. Do you know? I think I was just lucky, and I have not had any problems. My cable is UPC, but it's impossible to tell what the transmitters are. At least I can not make it out with my eyes, and it doesn't say anywhere on the box.
Not sure what you're looking for, but if you post a picture and model # it should be easy to figure out.
SC APC is green and SC UPC is blue. I haven't seen any converters use green, I think UPC is most popular. I don't think a SC APC will fit in a UPC port.. it shouldn't physically fit all the way in from what I'm reading.
This is from reddit
"SC/APC is NOT compatible with PC or UPC.

APC ferrule is angled 8 degrees to minimize reflection in the fiber. It's often used with analog signals. If you plug this in a PC or UPC connector, you will break the end of the ferrule, and possibly break the PC or at least scratch it badly.

PC and UPC are compatible. UPC is slightly rounded to make sure the contact with the core is solid. PC is flat, but it works well with UPC.

If you have an APC and a PC connector, you need a SC/APC to SC/PC patchcord.

Once again : plugging an APC into anything other than another APC will break stuff."


Images of the connector ends
http://www.fiber-optic-components.com/evolution-of-flat-pc-upc-and-apc-fiber-connectors.html
APC Angled:
https://www.flukenetworks.com/sites/default/files/APCCloseUp.PNG
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Re: where to go ? any ideas ?

Karl
I don't know if it has an angled connector of not:

https://www.vialite.com/resources/guides/apc-vs-pc-connectors/

https://www.reddit.com/r/networking/comments/4k9hr9/advice_on_interconnection_of_fibre_types_scapc_to/

The part of the connector inside the case is labeled "155Mbps T3R5 5V 25km SDN19031805591"

Searching on Duckduckgo and Google hasn't turned up anything useful yet.

---

What I found that's a little more interesting is that the power supply inside the HTB-1100S consists of a 3.3V AMS1117 linear regulator and a 470 uF electrolytic capacitor. So that's probably why it's clean when running off of a battery.  It also means that you don't need a full 5V.  According to the datasheet for the regulator (http://www.advanced-monolithic.com/pdf/ds1117.pdf), the maximum dropout voltage is 1.3V and the typical dropout voltage is 1.1V, so any power source with over 4.6V should work, and slightly lower voltages might also work.

I think I'll try running it off of four NiMH AA batteries in series (without an external regulator) and see how much current it draws and how long it takes for the voltage measured at the battery to drop below 4.6. If it drops too fast, I could switch to C or D cells or add another string of four AAs in parallel.
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Re: where to go ? any ideas ?

casper
Karl wrote
What I found that's a little more interesting is that the power supply inside the HTB-1100S consists of a 3.3V AMS1117 linear regulator and a 470 uF electrolytic capacitor. So that's probably why it's clean when running off of a battery.
Yes Karl, but check the traces going to the optical module. I think its power input is unregulated. I didn't dare to test it above 5V for that reason. But you're right, that it will probably run under 5. It will be interesting to see what limits you find.
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Re: where to go ? any ideas ?

Karl
Good point.  If the transceiver needs 5V, it definitely can't get it from the 3.3V regulator.

The four NiMH batteries in series will produce 4.8V when they're fully charged, so that should be safe.  Three alkaline batteries will give you 4.5V when they're new, but AAs would drop under 4.4V pretty fast.
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Re: where to go ? any ideas ?

Karl
In reply to this post by casper
It's hard to test the lower limit without an oscilloscope.  The only thing that goes wrong when the input voltage minus the dropout voltage is less than the intended output voltage (3.3V) is that the output won't be as smooth.  But since you're running from a battery, I think you could feed it 3.3V (or slightly more to account for any resistance in the AMS1117 and in the wires between it and your external regulator).
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Re: where to go ? any ideas ?

Karl
Here's a pic of the board:

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Re: where to go ? any ideas ?

Marc Martin
Administrator
In reply to this post by Karl
You could also get 5V from a wall-wart linear power supply, although you should verify how many amps it needs.

I've got two such 5V linear power supplies, one is good for up to 300ma, the other is good for up to 1A.

Although I have to put it through a couple of adapters to end up with a USB-A output.

Certainly switched 5V power supplies are commonplace, but you may not want that.

Marc

On October 29, Karl [via ES] <[hidden email]> wrote:
> The four NiMH batteries in series will produce 4.8V when they're fully
> charged, so that should be safe. Three alkaline batteries will give you
> 4.5V when they're new, but AAs would drop under 4.4V pretty fast.
 
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Re: where to go ? any ideas ?

Karl
This post was updated on .
In reply to this post by Karl
Looks like I was wrong about two important things:

1) Four fresh Tenergy NiMH AAs give me 5.8V, not 4.8V.

2) At least in the case of my LM317 regulator boards, I can't run 3.3V straight through even with a smooth power source like a battery.  I lose ~1V even if the output voltage is set to equal the input voltage.

Marc, yep, that should work well.  Good chance these will take less than 300 mA.  I'm using it now, so I will have test results soon.  Feels pretty good.
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Re: where to go ? any ideas ?

Karl
I hit a snag:  The power jack on the HTB-1100S isn't a normal 2.1mm x 5.5mm barrel plug.  I think it's 2.5mm x 5.5mm, but the plug I tried doesn't seem to make contact.

So I'm going to pop open the case and use alligator-clip jumper wires to connect the the battery pack to the solder-feet on the media converter's power jack .
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Re: where to go ? any ideas ?

Marc Martin
Administrator
There are adapters for that... for example:

https://www.amazon.com/dp/B01N812NKL/

Marc

>  I hit a snag: The power jack on the HTB-1100S isn't a normal 2.1mm x
> 5.5mm barrel plug. I think it's 2.5mm x 5.5mm, but the plug I tried
> doesn't seem to make contact.
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Re: where to go ? any ideas ?

Karl
Yep, I would have ordered some ahead of time if I'd known...  ended up taking the cable from the OEM power supply since I didn't feel like waiting.

It takes 350 mA to turn on, and 360 once the computer is connected.  The AAs don't work as well as I'd hoped due to voltage drop, so I ended up using 8 of them.  I could try using C cells in series instead.

There's some modest high-pitched noise on my AM radio (a Radio Shack RS-467) when I hold it near the converter or the ethernet cable, but a lot less that what the laptop itself emits.  (I tested the laptop separately with the ethernet and AC adapter disconnected, and also with only the AC adapter connected.)

Casper was too polite to say this the other day, but obviously you don't want to go too far under 5V on the input power if the optical transceiver is unregulated.  I was hung up on the presumption that it *must* be, so it didn't sink in until after I got a good night of sleep (overdue).  So the idea of running it without an external regulator is a no-go for now.
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Re: where to go ? any ideas ?

casper
Karl, for the regulator I got these. Prepare your wallet for the huge expense :)
They call it a buck regulator, but it's just a regular linear one.

https://www.ebay.com/itm/5PCS-AMS1117-1-2-5V-DC-Jack-Step-down-Buck-Voltage-Convertor-Power-Supply-Module/163081375537

I think you did pretty well considering such a short time. I took me over 6 months to even power on the converters the first time. That's how slowly I progressed. Partly because of CFS exhaustion, and partly because I ran into the same problems you did, and gave up until I figured out the next step.

I also blew up one regulator in the process, so it's good that they come in packs of 5.
Protip; don't connect a high amp power supply with plus and minus reversed to the regulator.




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Re: where to go ? any ideas ?

Karl
Thanks, Casper :)

I had a few extra regulators, so that's what it's powered from now.

The reason I wanted to omit the external regulator is that I already have a lot of batteries to charge, and not enough clean chargers.
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Re: where to go ? any ideas ?

Karl
FWIW, this is the type I used:

https://www.ebay.com/itm/LM317-DC-DC-Buck-Step-Down-Converter-5V-40V-To-1-2V-37V-Linear-Voltage-Regulator/322584903799

Yours has the advantage that the regulator chip it uses can tolerate reverse voltage (which can happen accidentally pretty easily).

I also have some of these:

https://www.ebay.com/itm/New-Assembled-LM317-LM337-Dual-Power-Adjustable-Regulated-Power-Supply-Board/272403680347

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